Apparatus for classifying particulate material



May 13, 1969 S NER ET AL 3,443,687

APPARATUS FOR CLASSIFYING PARTICULATE MATERIAL Filed Sept. 14, 1966 Sheet of 3 May 13, 1969 H. DEUSSNER ET AL 3,443,687

APPARATUS FOR CLASSIFYING PARTICULATE MATERIAL Filed Sept. 14, 1966 Sheet 2 of 5 FROM BLOW/7? N Fig. 3

May 13, 1969 H. DEUSSNER ET AL APPARATUS FOR CLASSIFYING PARTICULATE MATERIAL Filed Sept. 14. 1966 Sheet 3 of 3 '2 o 29 \o f la 00 Q i '5 i a o o o a O o o o 0 0 o 0 9i 9' O o o 0 [4 I0 0 I5 D Fig. 4

FROM BL OWE United States Patent 3,443,687 APPARATUS FOR CLASSIFYING PARTICULATE MATERIAL Herbert Deussner, Cologne-Dellbruck, and Hugo Schmitz,

Beckum, Germany, assignors to Klockner-Humboldt- Deutz Aktiengesellschaft, Cologne-Deutz, Germany, a corporation of Germany Filed Sept. 14, 1966, Ser. No. 579,362 Claims priority, application Germany, Sept. 21, 1965, K 57,185 Int. Cl. B03b 1/00 US. Cl. 209-3 Claims Our invention relates to apparatus for classifying particulate material.

As is well known, it is possible to classify particulate material by separating the particles thereof according to their different sizes and/ or weights, by means of a streaming fluid which may be either a gas or a liquid. This separating action takes place primarily because of the influence of a pair of differently directed forces on the particles, these forces being the inertia of the particles themselves and the force of the flowing fluid. The inertia forces acting on the particles correspond to the moving energy inherent in the particles themselves at the place where their classification occurs, while, on the other hand, the force of the flowing fluid is exerted on the particles from the fluid medium. The direction of movement of the individual particles will, therefore, take place as determined by the predominance of one of these forces or the predominance of the other of these forces in accordance with which of these forces is the more powerful.

There are at the present time many different types of known air separators operating according to the above principles. With most of the known devices the particulate material which is to be classified is centrifugally thrown from a rotary distributor and while suspended in a trajectory situated beyond the rotary distributor, the particles are subjected to the influence of a stream of air which acts as the separating or classifying medium and which is directed perpendicularly with respect to the direction of the trajectory of the particles. In this way it is intended that the relatively fine particles be separated from the relatively coarse particles. The fine particles carried along with the air stream are subsequently separated therefrom. The rotary distributor can take the form of a plate which turns about a vertical axis or a roller which turns about a horizontal axis and in both cases the particulate material is thrown substantially horizontally while the air stream is directed upwardly.

Classifiers of the above type have the disadvantage of requiring the fine and coarse particles to cross each other in an uncontrollable manner during the actual classification or separation of the particles, so that as a result a considerable fraction of the fine particles are necessarily carried away in an undesired manner with the coarse particles. While attempts to avoid this drawback have been provided, such as directing the coarse particles by bafiies in the form of suitable louver arrangements or the like, again to the air stream so that the latter will engage the coarse particles a second time, this air stream in this case must again pass through the trajectory of the centrifugally thrown particles, so that this expedient is more or less self-defeating and does not contribute a good solution to the problem.

A further drawback of the known classifying apparatus resides in the fact that the larger the capacity thereof the larger the diameter of the classifying chamber. If the size of the classifying chamber is not increased with an increase in the rate of classification of the particles,

3,443,687 Patented May 13, 1969 then the compactness of the particles in the trajectory along which they are centrifugally thrown will become too great to permit for an efficient flow of the air stream therethrough. However, because of the pressure prevailing in the classifier the inertia forces of the individual particles centrifugally thrown along the trajectory by the rotary distributor drops ofi very sharply as the particles move outwardly along their trajectory, and as a result in classifiers of relatively large size it is extremely difficult to provide an efficient classification for fine particles.

This problem has never been satisfactorily solved, even though various expedients have been resorted to, such as providing frustoconical passages through which the air stream is directed spirally or such as by providing separating chambers of elliptical configuration and directing the air into the latter both from above and from below.

It has also been proposed to provide a purely mechanical separation by situating separating blades in the stream of flowing particles so as to direct part of the stream along one side of the blade and another part on the other side of the blade, but experience has shown that such expedients can produce only an extremely coarse degree of classification, so that a sharply defined separation of fine and coarse particles can be achieved.

In summary, therefore, the previously known methods and apparatus for classifying particulate material can, on the one hand, only provide a disordered undefined degree of separation, and on the other hand, particularly in the range of fine particles the known methods and apparatus provide a degree of separation which becomes qualitatively poorer as the capacity of the separation increases.

It is, therefor, a primary object of our invention to provide particle classification which will avoid the above drawbacks.

In particular, it is an object of our invention to provide a classifying apparatus where the limit of classification is to a wery great extent independent of the capacity or size of the apparatus.

A further object of our invention is to provide an apparatus which will be capable of achieving a preliminary classification of the particles prior to actual separation thereof.

Also, it is an object of our invention to provide an apparatus which will eliminate the possibility of turbulence at the inner periphery of a whirling stream of particles.

Also, the objects of our invention include the provision of an apparatus which will produce the actual separation and classification of the particles while the latter move through a relatively short distance.

Also, the objects of our invention include the provision of an apparatus which will not compel the finer particles to cross the paths of the coarser particles.

An additional object of our invention is to provide a structure which will take advantage of the weight of the particles themselves in achieving the classification thereof.

Also, the objects of our invention include the provision of an apparatus in which the feeding of the particles into the apparatus is simultaneously effected together with at least part of the separating action.

Primarily, the structure of our invention includes a whirl chamber means for producing a whirling fluid stream in which the particles to be classified are suspended, this whirl chamber means of our invention having an outer wall and an inner space which is at least partly surrounded by the outer wall and around which the whirling fluid stream flows. A feeding means communicates with the interior of the whirl chamber means for feeding thereto the particulate material which is to be classified, and a passage means also communicates with the whirl chamber means for directing the primary fluid stream past the whirl chamber means along a path where the primary fluid stream tangentially impels the whirling fluid stream, this passage means of our invention having an upstream portion through which the primary fluid stream is directed to the whirl chamber means and a downstream portion through which the primary fluid stream is directed away from the whirl chamber means. This passage means of our invention is formed at an outer wall thereof and at a location which is aligned with the location where the primary fluid stream tangentially impels the whirling fluid stream with an opening through which the coarser particles will flow while the finer particles will be carried along with the primary fluid stream through the downstream portion of the passage means.

Our invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. 1 is a schematic representation of the principle of operation of the apparatus of our invention;

FIG. 2 illustrates a variation of the principle of operation of our invention;

FIG. 3 is a schematic sectional illustration of an apparatus for carrying out the principle shown in FIG. 1; and

FIG. 4 is a sectional elevation of one possible apparatus for carrying out the principle of our invention illustrated in FIG. 2.

In the schematic illustration of the fluid streams of FIG. 1, the primary fluid stream 1 generated by a fan or blower (not shown in the drawing) is directed upwardly toward the right, as viewed in FIG. 1, while it tangentially impels a whirling fluid stream 2 in a cylindrical chamber not shown in this diagrammatic figure. The particulate material 3 which is to be classified is fed to the whirling fluid stream 2, and the separated coarse particles 4 move horizontally to the right, as viewed in FIG. 1, across and beyond the primary fluid stream 1, while the fine particles 5 are carried along with the primary stream 1 downstream of the whirling fluid stream 2.

By its engagement with the whirling fluid stream 2, in the tangential manner indicated in FIG. 1, the primary stream 1 exerts shearing forces on the whirling fluid stream 2. The material 3 which reaches the whirling stream 2 at the region A is loosened up and accelerated in the whirling stream 2 so that the compactness of the particles is reduced and their speed of movement is increased. As a result of the rotary movement of the whirling stream 2, centrifugal forces act on the particles. The coarser particles follow the centrifugal force to a greater extent than the finer particles and for the most part become situated at the outer peripheral region of the field of centrifugal force. The finer particles also are exposed to the centrifugal force but are to a greater extent under the influence of the force of the flowing stream than the centrifugal force. As a result the finer particles are frictionally carried along by the fluid stream. The separation of the particles begins at that location where the primary stream 1 is in contact with the whirling stream 2. The coarse particles with the greater kinetic energy are in a position to move through the flowing primary stream 1 which has the width b. The finer particles, on the other hand, with the lesser kinetic energy, are carried along by the friction of the primary stream and thus flow with the latter. There is a relationship between the width b of the primary stream and the sharpness of the separation, in that the degree of sharpness of the separation will increase as the width b of the primary stream decreases. The limit of separation or classification, however, is dependent upon the speed of flow of the primary stream 1. Inasmuch as one of the features of our invention resides in providing an apparatus where the width b of the primary stream as well as the speed of flow thereof can with known structures be regulated, the structure of our invention provides, in addition to many other advantages, the advan- 4 tage of being to a very large extent adaptable to the requirements called for in the industrial classification of particulate materials.

According to the principle of operation shown in FIG. 2, the same basic principles are used as described above in connection with FIG. 1, and the same components are designated by the same reference characters. With the embodiment of FIG. 2 the primary stream 1 has a pair of auxiliary streams branching therefrom and individually flowing tangentially into the whirling fluid stream so as to provide a somewhat improved operation, as compared to FIG. 1. As may be seen from FIG. 2, the auxiliary stream 1b delivers the particulate material 3 which is to be classified to the whirling stream 2. Moreover, the particulate material which is situated at the outer periphery of the whirling fluid stream has the auxiliary stream 1a flowing therethrough so as to be further accelerated thereby. Otherwise, the embodiment of FIG. 2 operates in the same way as that of FIG. 1.

FIG. 3 shows a concrete embodiment of an apparatus operating according to the principle of FIG. 1. The whirling stream 2 is situated within a whirling chamber means 6 of circular cross section having an outer wall which extends around an inner central space about which the stream 2 whirls. A feeding means 7 communicates with an upper part of the whirling chamber means 6 for directing the particulate material 3 into the latter. A passage means 8, in the form of a suitable conduit, for example, directs the primary fluid stream 1 upwardly toward the right, as viewed in FIG. 3, and this passage means 8 communicates freely with a lower portion of the whirling chamber means 6, the passage means 8 extending tangentially with respect to the circular chamber means 6. The primary fluid stream is generated by a fan or blower not shown in the drawing. This passage means 8 has an outer wall formed with an opening 9 at a location aligned with the place where the primary stream 1 tangentially is in contact with the whirling stream 2, and the coarser particles 4, which are heavier and/or larger, flow out to the opening 9 into a particle collecting chamber 10 capable of being closed by a rotary gate valve 11 so that air cannot enter upwardly through the collecting chamber 10 while at the same time during turning of the gate 11 the particulate material 4 can be discharged from the collecting chamber 10.

Within the whirling stream 2 the particulate material is accelerated and pre-classified. The coarser particles flow transversely across the primary stream 1 and move through the opening 9 into the chamber 10. The fine particles S are instead carried along by the primary stream 1.

FIG. 4 shows in a sectional elevation an embodiment of a structure for carrying out the principle of FIG. 2. The section of FIG. 4 is taken in a vertical plane which includes a vertical central axis of the apparatus, and the apparatus is circumferentially constructed in a circular manner about its central vertical axis. In this embodiment the whirling chamber means 6' has, in plan, an endless configuration which may be circular or polygonal. Thus, in this embodiment the whirling fluid stream is of a ring-shaped toroidal configmration with the inner space which is at least partly surrounded by the outer wall of the chamber means 6 extending along a circle, and the whirling stream flows around this ring of space in radial planes which include the cenral axis of the apparatus, as indicated in FIG. 4. Thus, in the embodiment of FIG. 4 the whirling chamber means 6' surrounds a central axis which does not pass through the whirling chamber means 6', while in the embodiment of FIG. 3 the chamber 6 also surrounds a central axis, but in this case the central axis passes horizontally through the whirling chamber means 6 of FIG. 3.

Those components of FIG. 4 which are the same as or correspond to those of FIGS. 1-3 are indicated by the same reference characters.

With the construction shown in FIG. 4, the separating air 12, generated by a fan or blower, not shown in the drawing, enters through a pipe 13. Part of this air 12 forms the primary fluid stream 1 in a frustoconical passage 8'. Thus, the passage means 8 of the embodiment of FIG. 4 is defined on the one hand by a lower frustoconical wall 14 and an upper wall which forms the bottom wall of an air-guiding member 16 of double-frustoconical configuration. Thus, the upstream portion of the passage means '8 of FIG. 4 for the primary fluid stream 1 is defined by the lower frustoconical member 15 of the double-frustocone 16 and by the wall 14, part of the stream 12 branching into the space defined between the walls 14 and 15 to form the upstream portion of the primary fluid stream 1.

The double-cone 16 has a central pipe 17 passing therethrough, and the central axis of the apparatus of FIG. 4 also passes coaxially through the pipe 17 which is open at its opposite ends. The wall 14 is carried by the top end of the pipe 13 and the wall 15 is supported in spaced relation to the wall 14 by suitable pins carried by and extending between the Walls 14 and 15 and having a cross sectional configuration which may be streamlined in the direction of upward flow of the stream 1, so that in this way the unit 16 is supported on the wall 14 in spaced relation thereto. That part of the stream 12 which does not form the primary fluid stream 1 between the walls 14 and 15 continues to flow upwardly through the pipe 17.

A second air guide is situated coaxially above the double-cone 16 and has a central pipe 19 coaxial with and of a smaller diameter than the pipe 17. This pipe 19 is also open at its opposite ends. The unit 20 has a lower frustoconical wall spaced from the upper wall of the unit 16 to define therewith a frustoconical passage through which the auxiliary airstream 1a branches into the whirl chamber means 6'. That part of the stream which flows upwardly beyond the pipe 17 and does not form part of the auxiliary stream 1a continues to flow upward through the pipe 19. In this case also suitable supporting pins which may be of streamlined cross section are carried by the upper wall of the unit 16 and engage the lower wall of the unit 20 to support the latter in the illustrated space relation with respect to the unit 16.

The apparatus is provided at its upper part with a driving motor 21 which is operatively connected to and rotates a rotary distributing plate 22 which is coaxially positioned with respect to the co-axial pipes 17 and 19. This rotary distributing plate 22 is provided with fan blades 23 and a central lower opening 24 through which the air is sucked from the pipe 19 into the spaces between the fan blades 23 to be directed outwardly therefrom along the upper surface of the distributing plate 22. The distributing plate includes a lower wall 25 .and an upper wall between which the fan bades 23- are located, these fan blades fixing the lower wall 25 to the upper wall of the distributing plate, and the feeding means 7 is situated above the plate 22 for feeding the particulate material 3 which is to be classified thereto in the manner shown schematically in FIG. 4. The plate 22 distributes the particulate material 3 and throws it centrifugally toward the cylindrical wall 26 of the apparatus. This cylindrical wall 26 forms the inner wall of a third air-guiding unit 27 which together with the units 20 and 16 form the air-guiding units indicated in FIG. 4. Thus, the distributing plate assembly 22 serves not only to centrifugally distribute the particulate material but also to suck the air from the pipe 19 and to direct it radially outwardy toward the cylindrical wall 26 together with the particulate material 3.

The units 16, 20 and 27 have the walls which define the whirling chamber means 6 of this embodiment. Thus, the upper frustoconical wall of the unit 16, the lower outer frustoconical wall of the unit 20, and the lower frustoconical wall of the unit 27 define the walls of the whirling chamber means 6, actually forming the outer wall thereof. In this way the whirling chamber means 6 has the endless configuration which may be circular or polygonal and which is concentric with the vertical central axis of the entire apparatus. The passage 18 directs the auxiliary stream 14: tangentially in the whirling chamber means 6', and the annular gap 28 between the cylindrical wall 26 and the unit 20 forms a passage means through which the additional auxiliary stream 1b of FIG. 2 enters into the whirling chamber means 6'. These auxiliary streams enter tangentially into the toriodal whirling stream situated in the chamber means 6'. Of course, the passage means 28 also serves to direct the particulate material into the whirling chamber means 6'. At its lower portion, the chamber means 6' is in open communication with the primary passage means 8' through which the primary fluid stream 1 flows. The wall 14 has an upper frustoconical portion fixed at its outer periphery to the outer wall 29 of the housing of the apparatus, and this upper wall portion of the wall 14 is separated from the lower portion thereof by the annular gap 9' which is situated opposite the location where the primary fluid stream tangentially engages the whirling fluid stream, so that the coarser particles, which are heavier and/or larger, can flow through the opening 9' in the manner described above. The outer housing wall 29 has a lower frustoconical portion which defines with the wall 14 the collecting chamber 10 in which the coarser particles are collected and down which they can fall into the discharge conduit 30 which surrounds and is fixed to the pipe 13 and which communicates at its bottom end with the rotary gate valve 11' formed with the cells illustrated at the lower portion of FIG. 4 for receiving the particulate material and discharging the latter during rotation of the gate 11 while at the same time preventing air from flowing up to the conduit 30 into the collecting chamber 10.

The upper cylindrical portion of the outer housing wall 29 defines with the outer wall 31 of the air-guiding unit 27 the downstream portion 32 of the passage means for the primary fluid stream 1. The fine particles flow with the primary fluid stream downstream of the whirling chamber means 6 upwardly through the annular cylindrical passage 32 which communicates with an annular discharge passage 33 for the finer particles.

The material distributed by the rotary distributing plate 22 reaches together with the auxiliary stream 1b the interior of the ring-shaped whirling chamber means 6", through the annular gap 28, and the stream within the chamber means 6' is whirled by the tangential contact thereof with the upwardly flowing primary stream 1, this whirling of the air within the chamber means 6' being intensified by the additional auxiliary streams delivered to the chamber means 6 through the passages 28 and 18. The material which is situated at the outer portion of the whirling stream in the chamber 6 is loosened and has its compactness reduced by the auxiliary stream 1a flowing into the chamber 6' through the passage means 18. This auxiliary stream 1a serves to loosen fine particles from coarse particles to which they may happen to cling, and then these separated fine particles are frictionally carried along by the fluid streams. At that location where the whirling fluid stream and the primary fluid stream from the passage means 8' tangentially engage each other, the separation of the coarse and fine particles from each other begins. The coarse particles with the greater potential energy cross through the width b of the primary stream and reach the annular opening 9' through which these coarse particles move into the collecting chamber 10. They slide therein downwardly along the inner surface of the housing wall. The fine particles, on the other hand, are frictionally dragged along by the primary stream and are taken by the latter upwardly along the downstream portion 32 of the passage means for the primary stream, leaving the apparatus together with the primary stream at the outlet 33. From the outlet 33, the

U primary fluid stream together with the fine particles therein are directed to an illustrated separator where the solid particles and fluid medium are separated one from the other.

In order to obtain optimum operating conditions, it is possible to adjust the individual streams with devices known in the fluid-handling arts, such as, for example, by way of suitable throttling slide valves or by air-guides which control the width of the passages through which the fluid flows. In addition it is also possible to regulate the entire amount of fluid separating medium which floiws through the apparatus.

Thus, with the apparatus of the invention the passage means for the primary fluid stream 1 freely communicates with a lower portion of the whirling chamber means and in fact it is the movement of the primary fluid stream past and in communication with the whirling chamber means which creates therein the whirling stream which at its outer periphery is tangentially engaged and driven by the primary fluid stream. The particulate material which is delivered into the whirling stream progresses to a greater or lesser distance into the latter, has its compactness reduced therein, and is preliminarily accelerated and preliminarily classified as a result of the centrifugal forces in the whirling stream, so that in this way the coarser particles become situated in the region of the outer wall of the whirling fluid chamber means while the finer particles become more concentrated toward the inner portion of the \whirling stream. The particles are centrifugally advanced from the iwhirling fluid chamber means into the passage means for the primary fluid stream where the separating medium will initially engage the coarser particles which because of their larger inertia will move transversely through the separating medium and through the openings 9 or 9. The fine particles, on the other hand, are carried along by the primary fluid stream.

Thus, with the apparatus of our invention the particulate material which is to be classified undergoes a certain pre-classification in the whirling fluid chamber means while at the same time the particles are provided in the whirling fluid chamber means with the forces of inertia which prepare the particles for the actual separation which takes place at the relatively short distance where the primary stream engages the whirling stream. It is to be noted that with the structure of our invention there are no elements engaging the inner periphery of the whirling stream so that there is no creation of undesirable peripheral turbulence which would otherwise be provided if there were in fact an inner wall at the region where the inner portion of the whirling stream is situated. Thus, any undesirable influences on the operation by such an inner wall which would create undesirable peripheral turbulence is avoided with our invention. Thus, the particles which have been pre-classified to some extent in the whirling fluid are then engaged and separated by the primary fluid stream which requires only a small distance of engagement with the whirling stream to effect the desired separation. By situating the parts so that the primary stream initially engages the coarse particles, the fine particles need not cross the path of the coarse particles. Moreover, by arranging the primary stream so that it intersects the whirling stream at a lower portion thereof, advantage is taken of the weight of the particles in carrying out the classification of our invention.

By providing the structure shown in FIG. 4 according to which the whirling fluid chamber means 6 is of circular or polygonal configuration and is of a closed, endless form, there is the particular advantage that in order to provide different capacities it is only necessary to change the diameter of the chamber means 6', while all of the rest of the apparatus can be maintained at the same dimensions and operating conditions, so that the same classification conditions will be reliably maintained for different sizes of classifiers.

As was pointed out above, the auxiliary streams 1a and 1b serve to further accelerate the iwhirling fluid stream while the stream 1a serves additionally to contribute to the feeding of the particulate material into the whirling fluid stream.

We claim:

1. In an apparatus for classifying particulate material according to particle size and/or weight, whirl chamber means having an outer wall and an inner space at least partly surrounded by said outer wall, feeding means communicating with said whirl chamber means for feeding thereto particulate material which is to be classified, and passage means extending tangentially to said whirl chamber means at a part of said outer wall thereof and communicating with said inner space of said whirl chamber means for directing a primary fluid stream tangentially with respect to and in engagement with a whirling fluid stream located in said inner space of said whirl chamber means, said passage means having an upstream portion directing the primary stream of said whirl chamber means and a downstream portion directing the primary stream away from said whirl chamber means, and said passage means including an outer wall formed in alignment with the location where said passage means communicates with said whirl chamber means with an opening through which heavier or larger particles will flow to be separated from finer or lighter particles carried along with the primary stream in the downstream portion of said passage means.

2. The combination of claim 1 and wherein said whirl chamber means has upper and lower portions, and said passage means communicating with said whirl chamber means at said lower portion thereof.

3. The combination of claim 1 and wherein said whirl chamber means is of an endless configuration and surrounds a predetermined axis.

4. The combination of claim 1 and wherein at least one additional passage means communicates with said whirl chamber means for directing an auxiliary fluid stream into the latter.

5. The combination of claim 4 and wherein said additional passage means communicates with and forms part of said feeding means for also directing particulate material through said additional passage means into said whirl chamber means.

6. The combination of claim 1 and wherein said whirl chamber means is of substantially circular configuration and surrounds a substantially horizontal axis which extends through said whirl chamber means and around which the whirling fluid stream flows, said axis passing through said inner space of said whirl chamber means, and said passage means directing said primary stream upwardly and communicating with said whirl chamber means at a lower portion thereof, part of the primary stream which is directed upwardly by said passage means entering into said whirl chamber means to whirl therein and form said whirling fluid stream.

7. The combination of claim 1 and wherein said whirl chamber means is of an endless configuration and surrounds and is spaced from a predetermined axis, said inner space of said whirl chamber means having the configuration of a ring and said whirling fluid stream also having the configuration of a ring and having a whirling motion in radial planes which include said axis, said classifying apparatus including a double-cone having a lower wall forming part of said passage means and an upper wall forming part of said whirl chamber means, said double-cone having an axis coinciding with said predetermined axis.

8. The combination of claim 7 and wherein said passage means for said primary stream includes a lower frustoconical wall spaced from said lower wall of said double-cone to define with the latter a partly conical space forming the upstream portion of said passage means.

9. In an apparatus for classifying particulate material according to particle size and/or weight, whirl chamber means for enclosing a whirling fluid stream, said Whirl chamber means having an outer wall and an inner space at least partly surrounded by said outer wall and around which said whirl chamber means forms the whirling fluid stream within said outer wall, feeding means communicating with said whirl chamber means for feeding thereto particulate material which is to be classified, and passage means communicating with said whirl chamber means at a part of said outer wall thereof for directing a primary fluid stream tangentially with respect to and in engagement with a whirling fluid in said whirl chamber means, said passage means having an upstream portion directing the primary stream to said whirl chamber means and a downstream portion directing the primary stream away from said whirl chamber means, and said passage means including an outer wall formed in alignment with the location Where said passage means communicates with said whirl chamber means with an opening through which heavier or larger particles will flow to be separated from finer or lighter particles carried along with the pimary stream in the downstream portion of said passage means, said whirl chamber means being of an endless configuration and surrounding and spaced from a predetermined axis, said inner space of said whirl chamber means having the configuration of a ring and said whirling fluid stream also having the configuration of a ring and having whirling motion in radial planes which include said axis, said classifying apparatus including a double-cone having a lower wall forming part of said :passage means and an upper wall forming part of said whirl chamber means, said double cone having an axis coinciding with said predetermined axis, said whirl chamber means having an upper annular inlet through which the particulate material is fed by said feeding means into said whirl chamber means, said feeding means including a rotary distributing plate receiving the particulate material and centrifugally throwing the particulate material outwardly from said plate to said annular inlet of said whirl chamber means, said d0uble-cone being formed with a central passage through which said predetermined axis extends and communicating with said rotary plate, said plate carrying fan blades which suck fluid through said passage of said doublecone to said rotary plate to be directed from said rotary plate to said inlet of said whirl chamber means, so that part of the whirling ring-shaped stream therein is derived from fluid which enters with the particulate material into said Whirl chamber means.

10. The combination of claim 9 and wherein said whirl chamber means is formed with an additional inlet communicating with said passage of said double-cone to receive fluid therefrom for directing additional fluid into said whirl chamber means to accelerate and augment the flow of whirling fluid therein.

References Cited UNITED STATES PATENTS 2,828,011 3/1958 Whitby 20920 3,113,099 12/1963 Schmitz 209 FOREIGN PATENTS 684,759 4/ 1964 Canada.

FRANK W. LUTTER, Primary Examiner.

US. Cl. X-R. 209l37, 143 

1. IN AN APPARATUS FOR CLASSIFYING PARTICULATE MATERIAL ACCORDING TO PARTICLE SIZE AND/OR WEIGHT, WHIRL CHAMBER MEANS HAVING AN OUTER WALL AND AN INNER SPACE AT LEAST PARTLY SURROUNDED BY SAID OUTER WALL, FEEDING MEANS COMMUNICATING WITH SAID WHIRL CHAMBER MEANS FOR FEEDING THERETO PARTICULATE MATERIAL WHICH IS TO BE CLASSIFIED, AND PASSAGE MEANS EXTENDING TANGENTIALLY TO SAID WHIRL CHAMBER MEANS AT A PART OF SAID OUTER WALL THEREOF AND COMMUNICATING WITH SAID INNER SPACE OF SAID WHIRL CHAMBER MEANS FOR DIRECTING A PRIMARY FLUID STREAM TANGENTIALLY WITH RESPECT TO AN IN ENGAGEMENT WITH A WHIRLING FLUID STREAM LOCATED IN SAID INNER SPACE OF SAID WHIRL CHAMBER MEANS, SAID PASSAGE MEANS HAVING AN UPSTREAM PORTION DIRECTING THE PRIMARY STREAM OF SAID WHIRL CHAMBER MEANS AND A DOWNSTREAM PORTION DIRECTING THE PRIMARY STREAM AWAY FROM SAID WHIRL CHAMBER MEANS, AND SAID PASSAGE MEANS INCLUDING AN OUTER WALL FORRMED IN ALIGNMENT WITH THE LOCATION WHERE SAID PASSAGE MEANS COMMUNICATES WITH SAID WHIRL CHAMBER MEANS WITH AN OPENING THROUGH WHICH HEAVIER OR LARGER PARTICLES CARRIED ALONG WITH THE PRIMARY STREAM IN THE DOWNSTREAM PORTION OF SAID PASSAGE MEANS. 